Electric switch



May 4 1926.

' 1,583,598 G. s.- LEDDICK ELECTRIC SWITCH I Original ile an- 2. 192}Invennor: George SLeddick; y M 21 His Abner-neg.

Patented May 4, 1926.

UNI-T ED s'rarres Perri; Ni?

GEORGE- s. LEnmeK,

Original application me January 2, 1923, serial K956113 '3i i d' h s p in filled pt m i' v 26,1924. Seria1 Noi740J12.

Beit known'that L, GEORGE S, LEDDIOK, a citizen of the United States,residing at Schenect dy, county of Scljiene'ctady, State of New York,have invented certain new and useful Improvements in- Electric Switches,of whichthe following is a description.

The present application is a"clivision of my" priora plication, SerialNo. 610,092} filed January-2', 1923. d

One of the" obfjects' 'ot the invention is the provision ofl'a simpleand effective device'forllifiniting' the speedoi operation of a switchshaft. p

A further-object of'theinvention isto" provide an'inipreved latchingarrangement for holding a plurality of switch meinbers in either of aplurality of, predetermined relative positionsanc'l for limitingthe'speed of operation 'ofthe switchmembers.

These, and other objects ottheinvention as will be either explainedfully hereinafter or as will be apparentto those skilled in the art, areattained in the electric switch which is shown-on: theaccom'panyingdrawing in which 1 shows a plan-view of the complete switch; 2 isadetail showing,

the latching? or speed limiting arrangement Figs. 8,. Land 5 aresimplified details showing. the various, relative positions. of the,relativelymovable switch members of the switch and the interlockingarrangement be tweentheswitch members and 1 Fig. 6 is a simplifieddiagram of a control system in which the switch of the invention is usedin the control of thefild circuit of a synchronous motor.

Referring to the drawings, the'electrie switch comprises a switch member10l and a pair of relatively movable switch members 11 and I l 'whichare interlocked with the switch member 10 so as to'eontrol the operationof the switch member 10. As shown in Figs. 3, 4 and 5, theswitchnieinbe'r i0 is biased te th e closed position that is, inengagement with the stationary Contact 12 b inea-ns of the coiled spring13; which sur rhund's aipo'st l4; which passes throughthe switch member10"and'the co1 1tact"tip"15 thereoct. The switch'memher 10. and the setof switch members 11 and 11 are arranged to control separate circuits,and by anin-' spectionot (Slit will lee-seen that'the switch a member'10- when in the closed p'osi t-ioneonn'ectsfthe'field winding; 16 of asy'n chronous' motor local circuitwl-iieh in eludes the resistor 17- sothat the synchro'-- nousniotor may be started as an induction motoruntil the speed thereof: has'increas ed' to substantial synchronism.When the the switch member 10 opened, the field winch" into,s'ynchro'nism with the alternating sup ply circuit 19 and the motor Willoperate as a synchronous motor. -Thi's is vonly oneot the uses of myinvention, and I can conceive .that the 1nvention may be applied to"other uses in which it isodesirablefthat these q-uence Oi 'OFGTHii lORof a plurality of rela-- tively" movable switch members shall pro p Theswitch members 11 mounted upon the shaft 20 which is mounted in thebearings 21 and 22, so that these.

"and 11 are By ref-' swltchmeml'aers 11 and'li are' closed and lere'nce. to. Figs. 3, 4 and 5,. it will'b e noted that there is aninterlocking connectionbetween the switch member 11 and the switchmemberlO so that the switch member 10 is controlied in its movement bythe switch rn'ernben 11. In Fig. ,4: :the two switch menibers are shownin their relative positions when both switch .members are in" theirrespective open position. It will be seen that the bent st1'ip25,' whichis seeiir'ed to the shaft 20 and also to the switch member 11,

is in ciiect an extension of the switch member 11 and serves as arcaminterlocking'eon-' nc-ctioirbetween the switch niemhers 11 and 10. lViththe switch member 11 in the full open position,the'upper end of theswitch member 10ji's engaged'by the'exten'sion 25-at' the. apex 26 01the angle so that't'he switch member lOfhis held 'in the open positionagainst the bias of the spring 13 which tends to close thesan'ie. Whenthe switch inemloerill is moved clockwise about its pivQ o'ta;l'suppo'rts a limiteddi'stance as shown in Fig.3 5,"tl ie upper .fen'd ofthe-switch member 1-) is permitted tomove counter-c1ockwise hyreas'onofthe action of the spring' 13 so that th I v ga'geinent" with thestationary contact 12 and i switch contact 15 will make enconnect thesynchronous motor field in a local circuit including the resistor 17(Figs. 5 and 6). If the clockwise movement of the switch member 11 iscontinued, the upper end of the extension 25 will engage the upper endof the switch member 10 and will move the switch member 10 to the openposition against the action of the spring 13 until this opening movementis arrested by the stop 27. The switch member 11 will make engagementwith its stationary contact 23 as shown in Fig. 3, there by connectingthe field of the synchronous motor to the said direct current source ofsupply 18. It will be observed from the foregoing description that acontinuous movement of the switch member 11 imparts one relativemovement to the switch members and then imparts a different relativemovement; that is, moving the switch men1- ber 11 toward the closedposition first permits the switch member 10 to move to the closedposition and then opens the switch member 10 before the switch member 11is moved to the closed position. It will also be observed that inopening the switch, a continuous movement of the switch member 11 in theopening direction first imparts one relative movement to the switchmembers and then a diiierent relative movement; that is, in moving theswitch member 11 from the closed position as shown in Fig. 3 towards thefull open position as shown in Fig. 4, at an intermediate position theswitch member 10 will be permitted to close as shown in Fig. 5, and willbe again returned to the open position when the switch member 11 hasreached the full open position as shown in Fig. i. This has an advantagein that, for example, when the switch is used for controlling the fieldof a synchronous motor as shown in Fig. 6, when the motor field isdisconnected from the supply circuit it is connected in a local circuitso as to reduce the current in the field circuit preparatory to finallyopening the motor field circuit. The above described interlockingarrangement, whereby operating acommon actuating means for, a pluralityof switch members in one direction first imparts one relative movementto the switch members and then imparts a different relative movement tothe switch members, is claimed in my prior application, Serial No.610,097, filed January 2, 1923, of which the present application is adivision.

For certain applications as, for example, in the control of the fieldcircuit of a synchronous motor as shown in Fig. 6, it is desirable thatthe speed of operation of the switch members be limited, and for thatpurpose I have provided the latching arrangement shown in Figs. 1 and 2which I shall now describe. I would have it understood that thislatching arrangement is not limited in its application to the particulararrangement of relatively movable switch members which I have previouslydescribed, but that this feature of my invention is applicable generallywhere it is desired to limit the speed of operation of a switch shaft.

Referring to Figs. 1 and 2, the handle 28 which is connected with theshaft 20 provides a common actuating means for the switch memberspreviously described. -A latching arrangement is provided whereby thishandle is held in any one of a plurality of predetermined positions andthe speed of operation of this handle thus limited. The spring presseddetent 29 provides a locking member which is carried by and moves withthe handle 28 and this detent cooperates with the stationary dial plate30, which may be mounted on the casing oi the switch, for holding thehandle 28 in any one of a plurality of predetermined positions and forlimiting the speed of operation of the handle. This detent 29 is anintegral extending part of a leaf spring having one end thereof securedto the handle 28 as indicated. In the upper end 01' the handle there isprovided an operating member tor the detent 29. This member takes.

the form of a resiliently mounted push but- 7 ton 31 which is normallybiased out of engagement withthe dial plate 30 by means or" the spring32, but when this button is depressed as shown in Fig. 1, the left handend thereof engages the resilient detent 29 and moves the same out ofengagement with the notched upper edge of the dial plate 30.

The operation of this part of my inven tion is as follows: In Fig. 2 thehandle of the switch is shown as in the running position. In order tomove the handle to the open position it is necessary to first press thebutton 81 so as to release the detent 29 from engagement with the notchin the upper edge of the dial plate 30. The handle may then be movedcounter-clockwise until the left-hand edge of the detent 29 slides underthe portion 33 of the dial plate 30.

Further movement of the handle in the counter-clockwise direction isarrested be cause of the fact that the pin of the push button 31 isarrested at the left-hand edge of the .slot in the dial plate 30. Thepush button must now be released to permit the handle to be moved untilthe detent 29 drops into the notch 34 thus arresting any furthermovement of the handle in this direction. The relative positions of theswitch members will now be as shown in Fig. 5. In order to continue thecounter-clockwise movement of the handle, it will be necessary to pressthe push button 31 again so as to thereby permit the detent 29 to slideunder the portion 35 of the dial plate, and by 31, move the handle 28 ashort moving the handle a short distance counter clockwise, the detentwill be engaged under the portion 85. However, further movement of thehandle is arrested until the push button 31 is released because of thefact that the end of the pin connected with the push button will engagethe left-hand edge of the slot 36. hen the push button has beenreleased, the handle may be moved a short distance counter-clockwiseuntil the detent 29 drops into'the notch 37. Further movement of thehandle counter-clockwise is thereby prevented. lhe relative. positionsof the switch members will now be as shown in Fig. t.

in order to close the switch it will be necessary to press the pushbutton with the clockwise until thepin associated vpush button 31engages with the right-hand edge of the slot 38, then release the pushbutton out of engagement with the slot 38 so that the handle may bemoved to the middlecoperative position at which the detent 29 willarrest further movement. In order to more from the middle position tothe final position, that shown in Fig. 2, it will be necessary to againpress the push button 31, more the handle 28 to a short distanceclockwise until the detent 29 engages under the portion 88 of the dialplate, then release the push button and finally move the handle to theposition'shown in Fig. 2.

It will be observed that a definite sequence I of operations must be hadin order to move. the handle from one definite position to anotherdefinite position, and that this sequence of operations will limit .thepermissible speed'of operation of the handle so as to thereby preventthe handle from being thrown directly from one extreme position to theother. It will also be observed that the latching arrangement serves topositively hold the handle in any one of the predetermined definitepositions of the handle so that there is no possibility of unintentionaloperation of the switch members.

It will also be observed that the means disclosed herein for moving theshaft from one positionto another is avery simple, compact, andeconomical construction which will not easily get out. of order or needany considerable repair. These advantages are due detent 2-9, and

member 11,

distance essentially to theuse of a leaf spring at tached at one end tothe handle 28, with a portion thereof extending to constitute the to thearrangement of this spring and the together over the opposite sides ofthe not lied and perforated plate 30, and to the location of this springopposite the push button 31. This structure is in itself very simple andcompact and moreover permits the pin of the push button 31 to actdirectly on the leaf spring and cooperate directly with the plate 30,thus dispensing with intervening additional space-consuming partsheretofore used in devices of this kind.

in accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

An electric switch comprising a shaft, switching mechanism located onsaid shaft, a handle attached to said shaft for operation thereof, ahand knob on said handle, a plate over the face of which the end of thehandle slides, a leaf spring mounted on said handle and slidable overthe'back of said plate and extending opposite to said knob, the saidplate having notches and holes corresponding to the notches, anextension from said spring adapted to successively engage said notches,a pin extending through said knob and movable through said holes andinto engagement with the leaf spring to disengage said spring from saidnotches, the size and location of each hole with respect to the pin andcorresponding notch being such as to permit the pin to hold the springdisengaged from a notch until the handle is moved beyond the point wherethe spring can engage said notch and to prevent the movement of thehandle to a point where the spring can engage another notch without thewithdrawal of the pin from said hole.

In Witness whereof, I have hereunto set my hand this th day ofSeptember, 1924.

' GEORGE S. LEDDICK.

handle 28 so that they slide

